Controlling heat capacity in a thermal concentrator using metamaterials: Numerical and experimental studies

International audience ; We developed two thermal concentrators, one with a 2D design ofuniform thickness and another with a 3D design, using thecoordinate transformation technique and metamaterials. Bystructuring the thermal conductor, we were able to achieve thedesired local density-heat capacity product ρC and anisotropicthermal conductivities. Homogenized thermal conductivities wereobtained from the boundary heat fluxes of the unit cells computedwith finite element simulations and taking into account thecylindrical symmetry. We fabricated the 3D concentrator using 3Dmetal printing and used a thermal camera for characterization. Bydesigning the unit cells to obtain the ρC values given by thecoordinate transformation, the time evolution characteristics ofthe metadevice are closer to those of an ideal concentrator whencompared to devices that solely consider anisotropicconductivities.